Microstructural Study of IF-WS2 Failure Modes

Inorganics

Jamie Cook²  Steven Rhyans²  Lou Roncase¹  Garth Hobson² 

[1] U.S. Navy’s Weapons Survivability Laboratory (WSL), Naval Air Warfare Center (NAWC), China Lake, CA 93555, USA; E-Mail:;Mechanical and Aerospace Engineering Department, Naval Postgraduate School, 700 Dryer Rd., Watkins Hall Rm. 305, Monterey, CA 93943, USA; E-Mails:

关键词: IF-WS₂;    shock absorbing structures;    fracture mechanism;   

DOI  :  10.3390/inorganics2030377

来源: mdpi

【 摘 要 】

This manuscript summarizes the failure mechanisms found in inorganic fullerene-type tungsten disulfide (IF-WS₂) nanoparticles treated with diverse pressure loading methods. The approaches utilized to induce failure included: the use of an ultrasonic horn, the buildup of high pressures inside a shock tube which created a shock wave that propagated and impinged in the sample, and impact with military rounds. After treatment, samples were characterized using electron microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, and surface area analysis. The microstructural changes observed in the IF-WS₂ particulates as a consequence of the treatments could be categorized in two distinct fracture modes. The most commonly observed was the formation of a crack at the particles surface followed by a phase transformation from the 3D cage-like structures into the 2D layered polymorphs, with subsequent agglomeration of the plate-like sheets to produce larger particle sizes. The secondary mechanism identified was the incipient delamination of IF-WS₂. We encountered evidence that the IF-WS₂ structure collapse initiated in all cases at the edges and vertices of the polyhedral particles, which acted as stress concentrators, independent of the load application mode or its duration.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.